Lancing devices are utilized for penetrating the skin of a human or animal subject at a lancing site to obtain a sample of blood or other body fluid for medical testing, as in blood-typing or blood-glucose testing. Known lancing devices commonly include a housing containing a drive mechanism, a charging mechanism for energizing the spring or other drive means of the drive mechanism, and a release mechanism for releasing the drive mechanism upon actuation. A lancet is typically propelled by the drive mechanism from a retracted position shielded within the housing to an extended position wherein a sharp tip portion of the lancet projects from the housing to prick the subject's skin at a desired lancing site. Many lancing devices further include a depth-control mechanism for varying the depth of penetration, for example by limiting the stroke of the lancet, or by adjusting the position of an endcap or other portion of the device relative to the lancet's path of travel.
The lancet is commonly a disposable and replaceable component that is removably mounted into a receiver or lancet carrier portion of the drive mechanism of the lancing device. A used lancet typically is removed from the lancet carrier after use and disposed of. A new, sterile lancet is then replaced into the lancet carrier for subsequent use. Lancets typically comprise a sharp metal tip in the form of a needle or blade. The needle or blade is typically embedded in a substantially rigid plastic body that has a size and shape configured for releasable engagement in the receiver or lancet carrier of a specified lancing device. The sharp tip of the lancet is typically embedded in a removable plastic shroud or cap to maintain sterility and prevent inadvertent sticks prior to use. The endcap and the body of the lancet may be formed as a single, unitary plastic molding with a notched or necked section of reduced thickness for facilitating detachment and removal of the endcap. The endcap may be replaceable onto the lancet after use to re-cover the sharp lancet tip for safety and hygienic purposes.
Known lancets are commonly configured for use in connection only with specified models of lancing devices or only with lancing devices having particular receiver dimensions. Some lancing devices have receivers that flex or expand during loading to grip the lancet body, and thus may accommodate lancets of varying dimensions, but typically only within a fairly narrow tolerance range. Thus, known lancets typically do not fit universally in different lancing devices that have a large variation of lancet receiver dimensions. For example, a lancing device having a receiver suited for lancets of 6-7 mm body diameter typically cannot receive a lancet having a body diameter of 8 mm, and will not grip a lancet having a body diameter of 5 mm. As such, users must be careful to select the correct size of lancet for their intended model of lancing device. This may present a challenge for users having reduced visual acuity. And a user having purchased lancets of incorrect size may be unable to test their blood sugar until lancets of the correct size can be obtained, possibly leading to adverse health effects.